1. Field of the Invention
The present invention generally relates to planning and optimization of a universal mobile telecommunication system (UMTS) based network. In particular, the present invention relates to detecting and reducing interference from several transmitters in a UMTS network.
2. Description of the Related Art
Traditional network planning and optimization of a wireless network relies on static methodologies for finding site locations, dimensioning and configuring the radio resources to meet specified traffic demand. Traditional network optimization methods find the best configuration(s) of the wireless network to maximize the performance, which typically starts with an already working wireless network, followed by analysis and calculations done by engineers using software and hardware tools with extensive simulations of the network. Once a better configuration is determined, the new configuration is manually implemented.
However, manual network optimization consumes a large amount of human resources and is a lengthy process that is performed only when needed or periodically. Therefore, usage of network resource is not maximized, quality of service is degraded and end users or customer satisfaction is reduced.
Additionally, UMTS based wireless networks offer soft handover features that allow a mobile station (MS) to be served by multiple transmitters. The transmitters that serve the MS simultaneously constitute the active set for that MS. However, signals received by the MS that are not sent by the transmitters in the active set are considered interference signals.
Existence of interfering transmitters may lead to reduced network performance by reducing the number useful signals received by mobile stations. Moreover, interfering transmitters may cause pilot pollution, which is a phenomenon that occurs when there are too many potential serving cells to choose from.
Therefore, it would be useful to implement an automated system for network planning and optimization that also reduces interference and maximizes overall network performance.